Load Module (LOADA-GM-364) Maximum Switch Rate / Optical Encoder Simulation

I am looking to simulate an optical encoder / odometer sensor for a test rig and planned on using the GHI Load module (LOADA-GM-364) to generate the pulse train (12-24 V).

Is there any documentation on the maximum switch rate the module can accomplish?
For my application, I am looking for 120 Hz, but wondered what the limit was.

Is there a better technique or module to use for this purpose?

That modules uses BCP55 transistors.

According to this:

Typical frequency is 180MHz.

You should be fine!